Ferrule assembly and methods thereof

ABSTRACT

A ferrule assembly for terminating at least one fiber of a ribbon cable in a ferrule, where the ferrule assembly is disposable in a housing of an optical connector, is provided. The ferrule assembly includes the ferrule having a mating face, at least one groove for receiving the fiber and at least one through-hole. The ferrule assembly also includes an alignment member holder having at least one alignment member and providing a first channel for the ribbon cable, the alignment member being insertable in the through-hole of the ferrule and having a first length such that an end of the alignment member extends beyond the mating face of the ferrule when the ferrule assembly is assembled. The ferrule assembly further includes a carrier body attachable to the alignment member holder, the carrier body having at least two biasing member capture portions, each of the biasing member capture portions providing an opening for capturing a biasing member therein when the alignment member holder and the carrier body are attached. The carrier body further provides a second channel for the ribbon cable, the second channel being disposed between the biasing member capture portions of the carrier body and being contiguous with the first channel when the alignment member holder and the carrier body are attached.

This application is a continuation of U.S. patent application Ser. No.10/324,816, filed Dec. 20, 2002, now issued as U.S. Pat. No. 7,204,016.

BACKGROUND OF THE INVENTION

The present invention relates to a ferrule assembly disposable in ahousing of an optical connector.

Fiber optic connectors that house optical fibers of a ribbon cable areknown. One common type of multi-fiber optical connector is themechanical transfer push/pull (“MTP”) connector. A conventional MTPconnector includes a connector housing and an MT ferrule assemblydisposed at least partially within the connector housing. FIG. 1, whichis FIG. 2 of U.S. Pat. No. 5,806,175 (with different reference numbers),is an illustration of an MTP connector. The '175 patent is incorporatedherein by reference.

As shown in FIG. 1, the MTP connector 10 includes a connector housingassembly 14 and an MT ferrule assembly 16 that is configured to bedisposed within the connector housing assembly 14. The MT ferruleassembly 16 typically includes an MT ferrule 18 that is forward biasedby a coiled spring 20 disposed between the ferrule 18 and a ferrulecarrier body 22. The ferrule 18 has through-holes (not visible) forreceiving alignment pins 26 of a pin holder 24. A ribbon cable 12 havingone or more ribbon fibers extends through the ferrule carrier body 22,the coiled spring 20, the pin holder 24 and is terminated in the ferrule18. A crimp ring 28 is slidable over an end of the ferrule carrier body22 to securely attach the MTP connector 10 to the ribbon cable 12 whencrimped. A strain relief boot 30 is placed over the crimp ring 28 toprotect the connection between the ribbon cable 12 and the MT ferruleassembly 16, as well as to provide strain relief for the ribbon cable12.

The process for assembling the MTP connector 10 of FIG. 1 is generallyas follows. The backing components, such as the strain relief boot 30,the crimp ring 28, the ferrule carrier body 22, the coiled spring 20,and the pin holder 24, are first assembled on the ribbon cable 12. Afterthe outer jacket of the ribbon cable 12 has been stripped, the fibersare disposed in the ferrule 18. Ends of the fibers in the ferrule 18 aretrimmed and the front surface of the ferrule 18 is polished so that theends of the fibers are coplanar with the front surface. The rest of theconnector 10 is then assembled.

The inventors of the present invention have recognized somedisadvantages of the MTP connector discussed above. For example, whenthe backing components are assembled on the ribbon cable prior totermination of the fibers in the ferrule, any mistake during theassembly (e.g., missing a component) would result in the need forre-terminating the ferrule and the disposal of the backing components.As the costs for the ferrules and the termination are significant, thisis a real concern. Also, because of the number of backing components andtheir assembly requirements, the process of assembly is difficult andcostly and potential damage to the backing components is a commonconcern.

What is desired, therefore, is a ferrule assembly for a connector thatcan address these and other disadvantages of the present connectors.

SUMMARY OF THE INVENTION

The objects of the present invention are achieved in one embodiment by aferrule assembly for terminating at least one fiber of a ribbon cable ina ferrule, where the ferrule assembly is disposable in a housing of anoptical connector. The ferrule assembly includes the ferrule having amating face, at least one groove for receiving the fiber and at leastone through-hole. The ferrule assembly also includes an alignment memberholder having at least one alignment member and providing a firstchannel for the ribbon cable, the alignment member being insertable inthe through-hole of the ferrule and having a first length such that anend of the alignment member extends beyond the mating face of theferrule when the ferrule assembly is assembled. The ferrule assemblyfurther includes a carrier body attachable to the alignment memberholder, the carrier body having at least two biasing member captureportions, each of the biasing member capture portions providing anopening for capturing a biasing member therein when the alignment memberholder and the carrier body are attached. The carrier body furtherprovides a second channel for the ribbon cable, the second channel beingdisposed between the biasing member capture portions of the carrier bodyand being contiguous with the first channel when the alignment memberholder and the carrier body are attached.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prior art MTP connector as illustrated in FIG. 2 of U.S.Pat. No. 5,806,175;

FIG. 2 is a perspective view of a ferrule assembly in accordance withthe preferred embodiment of the present invention;

FIG. 3 is an exploded view of the ferrule assembly of FIG. 2;

FIG. 4 is a perspective view of the alignment member holder of FIGS. 2and 3;

FIGS. 5 a-5 f show a method for terminating a ribbon cable in a ferruleand assembling an optical connector; and

FIG. 6 is a perspective view of the ferrule assembly of FIG. 2 with astrain relief member.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 2 shows a perspective view of a ferrule assembly in accordance withthe preferred embodiment of the present invention. The ferrule assembly50, which is disposable in a housing of an optical connector, generallyincludes an alignment member holder 60 and a carrier body 80. See FIGS.5 e and 5 f for exemplary illustration of a housing of an opticalconnector.

The alignment member holder 60, which is shown in greater detail in FIG.4, includes a first alignment member 62 and a second alignment member63. As will be described in greater detail below, the first and secondalignment members 62, 63 preferably have different lengths. Thealignment member holder 60 also includes first and second guides 64, 65,with the first guide 64 having a latch member 66 and the second guide 65having a latch member 67. While the figures show the latch members 66,67 as two hook-like protrusions on opposite sides of the first andsecond guides 64, 65, it should be apparent to one of ordinary skill inthe art that other latching methods and mechanisms may be employedwithout departing from the scope of the invention.

The alignment member holder 60 further includes a through-hole 68through which the first alignment member 62 is inserted such that theend of the first alignment member 62 extends beyond the alignment memberholder 60 in the mating direction M with a corresponding ferruleassembly. The alignment member holder 60 may also include anotherthrough-hole through which the second alignment member 63 is inserted.However, in the preferred embodiment of the invention, the secondalignment member 63 is integrally formed with the alignment memberholder 60. The alignment member holder 60 provides a first channel 69for a ribbon cable (shown in FIGS. 5 and 6).

The carrier body 80 includes a first biasing member capture portion 82and a second biasing member capture portion 83. The first biasing membercapture portion 82 provides an opening (not numbered) for capturing afirst biasing member 84 and the second biasing member capture portion 83provides an opening (not numbered) for capturing a second biasing member85. While the preferred embodiment of the invention shows the first andsecond biasing members 84, 85 as coiled springs, other biasing methodsand mechanisms may be employed as known in the art.

FIG. 3 is an exploded view of the ferrule assembly 50 of FIG. 2, andshows the first and second biasing member capture portions 82, 83 moreclearly. The first and second biasing member capture portions 82, 83also includes slots 86, 87 to engage the latch members 66, 67,respectively, of the alignment member holder 60. The first and secondguides 64, 65 of the alignment member holder 60 are insertable into theopenings of the first and second biasing member capture portions 82, 83.And the slots 86, 87 are configured to engage the latch members 66, 67so as to provide for slidable engagement between the alignment memberholder 60 and the carrier body 80. The latch members 66, 67 and theslots 86, 87 are positioned such that in order to disengage thealignment member holder 60 from the carrier body 80, the biasing members84, 85 must first be biased (compressed in the case of coiled springs).This prevents the accidental disengagement of the alignment memberholder 60 from the carrier body 80.

The carrier body 80 provides a second channel 89 for the ribbon cable.The second channel 89 is preferably disposed between the first andsecond biasing member capture portions 82, 83 and is contiguous with thefirst channel 69 when the alignment member holder 60 and the carrierbody 80 are engaged.

As shown in FIGS. 2 and 3, the carrier body 80 also includes a ferruleassembly release member, which is shown as first and second elongated,flexible grips 90, 91. While the preferred embodiment of the inventionhas two elongated, flexible grips, it should be apparent that oneelongated grip may be used, as well as other number or mechanisms formanual actuation may be used. In the preferred embodiment, the ferruleassembly release member is integrally formed with the carrier body 80.The operation of the ferrule assembly release member will be describedbelow.

The carrier body 80 further includes latches 93, 94 to enable thelatching of the ferrule assembly 50 to the housing of the opticalconnector. This is shown and described with respect to FIGS. 5 e and 5f. When a user grips and squeezes the elongated, flexible grips 90, 91toward each other, the latches 93, 94 become disengaged from the housingof the optical connector, thereby enabling the ferrule assembly 50 to bedisengaged from the optical connector housing. One latch, more than twolatches, or other mechanisms for latching may be used instead forlatching the ferrule assembly 50 the optical connector housing.

FIGS. 5 a-5 f show a method for terminating a ribbon cable 100 in aferrule 110 and assembling an optical connector 150. Unlike the priorart MTP connector 10 of FIG. 1, the ferrule assembly 50 of the presentinvention allows the ribbon cable 100 to be first terminated in theferrule 110 before any backing components must be assembled on theribbon cable 100. As known in the art, the process of terminating theribbon cable in the ferrule includes stripping an outer jacket of theribbon cable, disposing the one or more fibers of the ribbon cable inthe ferrule, trimming the ends of the fibers and polishing the ends ofthe fibers.

FIGS. 5 a and 5 b illustrate a dust seal member 120 being provided tothe ribbon cable 100. While this step is optional, it is desired to havethis step to provide better dust protection to the ferrule assembly. Thedust seal member 120 may be attached to the ribbon cable 100 by use ofan adhesive agent or by other means known in the art. Preferably, thedust seal member 120 is a Teflon® adhesive-coated insert or the likethat adheres to the ribbon cable 100. Note that the dust seal member 120could also be made from a porous filter material, which can blocksub-micron particles but allow air to pass. This would allow the ferruleassembly to be cleaned by a vacuum or the like.

The ferrule 110 is provided with a first through-hole 112 and a secondthrough-hole 113. Reference numeral 111 indicates a mating face of theferrule 110. After the alignment member holder 60 is preferably attachedto the carrier body 80, the ferrule 110 with the terminated ribbon cable100 is then disposed on the alignment member holder 60. The firstalignment member 62 is inserted in the first through-hole 112 and thesecond alignment member 63 is inserted in the second through-hole 113.This is shown in FIGS. 5 c and 5 d. Due to the different lengths of thefirst and second alignment members 62, 63, the first alignment member 62extends beyond the mating face 111 of the ferrule 110 while the secondalignment member 63 stays within the second through-hole 113 and isrecessed from the mating face 111 of the ferrule 110.

The ribbon cable 100 is disposed in the first channel 69 of thealignment member holder 60 and the second channel 89 of the carrier body80 (see FIG. 2). Along the second channel 89 of the carrier body 80,there is provided a cut-out 81 for engaging the dust seal member 120.The cut-out 81 is sized relative to the dust seal member 120 to providesome slidability of the ribbon cable 100.

FIGS. 5 e and 5 f show the assembled ferrule 110, alignment memberholder 60 and the carrier body 80 disposed in a housing 140 of anoptical connector 150. As shown, the housing 140 is configured toreceive two ferrule assemblies 50. Such an optical connector is referredto as a “duplex” connector. Note that while the connector shown is aduplex connector, the ferrule assembly of the present invention may workwith any connector configuration and is not intended to be limited to aduplex connector. The housing 140 includes slots 142 (bottom slot notvisible) to removably engage the latches 93, 94 of the carrier body 80.

FIG. 6 is a perspective view of the ferrule assembly of the presentinvention, with a strain relief member 160. The strain relief member 160includes a curved channel to provide strain relief to the ribbon cable100. Note that the strain relief member 160 is configured for a duplexconnector. However, the strain relief member may be configured for anynumber of ferrule assemblies.

Some of the advantages of the ferrule assembly of the present inventionhave been described in the Background Of The Invention section. However,there are additional advantages provided by the present invention. Forexample, unlike existing designs in which the biasing member of thecarrier body is exposed, the biasing members 84, 85 of the presentinvention are not exposed but rather disposed in biasing member captureportions 82, 83. This reduces potential for component damage andprovides a more stable movement in the mating direction. Also, becauseof the different lengths of the first and second alignment members 62,63, the ferrule assembly of the present invention allows forhermaphroditic mating. The position of the first and second alignmentmembers would be reversed on the mating ferrule assembly to allow thelonger alignment member to be received in the ferrule through-holeoccupied by the shorter alignment member of the mating ferrule assemblyand vice-versa. The hermaphroditic nature of the mating ferruleassemblies reduces the number of components necessary, makes inventoryeasier and facilitates manufacture and assembly. Still another advantageof the present invention is that the alignment member holder is guidedin the carrier body to allow movement only in the mating axis. This aidsin finer ferrule alignment.

While the ferrule assembly of the present invention has been designedfor a ferrule having at least one through-hole for receiving analignment member, it would be apparent to one of ordinary skill in theart that the present invention may also be used for a ferrule having nothrough-hole. In this case, the alignment member holder would not haveany alignment members. Thus, the alignment member holder may also bereferred to as a “ferrule holder”. In addition, while the preferredembodiment is to have a biasing member in each of the biasing membercapture portions, the present invention can also function with only oneof the biasing member capture portions having a biasing member. Thus,the biasing member capture portions may also be referred to as “guidereceiving portions” herein.

Having thus described the preferred embodiment of the present inventionwith sufficient particularity to enable those skilled in the art to makeand use the invention, and having described variations and modificationsof the preferred embodiment, it should nevertheless be appreciated thatstill further variations and modifications of the invention arepossible, and that all such variations and modifications should beconsidered within the scope of the invention.

1. A ferrule assembly disposable in a housing of an optical connector,the ferrule assembly for terminating at least one fiber of a ribboncable in a ferrule comprising: the ferrule having a mating face, atleast one groove for receiving the fiber and at least one through-hole;an alignment member holder having at least one alignment member andproviding a first channel for the ribbon cable, the alignment memberbeing insertable in the through-hole of the ferrule and having a firstlength such that an end of the alignment member extends beyond themating face of the ferrule when the ferrule assembly is assembled; acarrier body receiving at least a portion of the alignment member holderthrough a front opening thereof, the carrier body having at least twobiasing member capture portions, each of the biasing member captureportions providing an opening for capturing a biasing member thereinwhen the alignment member holder and the carrier body are attached. 2.The ferrule assembly of claim 1, wherein the alignment member holderincludes first and second guides insertable into the openings of thebiasing member capture portions such that when the alignment memberholder and the carrier body are attached, the alignment member holder ismovable only along the mating axis.
 3. The ferrule assembly of claim 2,wherein the first and second guides of the alignment member holderinclude at least one latch member to slidably attach the alignmentmember holder to the carrier body.
 4. The ferrule assembly of claim 3,wherein the latch member for the first and second guides is positionedon the first and second guides such that in order to disengage thealignment member holder from the carrier body, the biasing members ofthe carrier body must be biased.
 5. The ferrule assembly of claim 1,wherein the alignment member holder includes a through-hole and thealignment member is inserted into the through-hole of the alignmentmember holder such that the end of the alignment member extends beyondthe alignment member holder in the direction of the ferrule.
 6. Theferrule assembly of claim 1, wherein the ferrule further includes asecond through-hole and the alignment member holder further includes asecond alignment member, the second member being insertable in thesecond through-hole of the ferrule and having a second length such thatan end of the second alignment member stays within the secondthrough-hole and is recessed from the mating face of the ferrule whenthe ferrule assembly is assembled.
 7. The ferrule assembly of claim 6,wherein the second alignment member is integrally formed with thealignment member holder.
 8. The ferrule assembly of claim 1, wherein thecarrier body further includes a ferrule assembly release member, theactuation of which allows the ferrule assembly to be removable from thehousing of the optical connector.
 9. The ferrule assembly of claim 8,wherein the ferrule assembly release member is integrally formed withthe carrier body.
 10. The ferrule assembly of claim 8, wherein theferrule assembly release member comprises at least one elongated,flexible grip.
 11. The ferrule assembly of claim 8, wherein the ferruleassembly release member comprises two elongated, flexible grips.
 12. Theferrule assembly of claim 1, wherein the carrier body further includesat least one latch to latch the ferrule assembly to the housing of theoptical connector.
 13. The ferrule assembly of claim 1, wherein thecarrier body further includes at least two latches to latch the ferruleassembly to the housing of the optical connector.
 14. The ferruleassembly of claim 1, which further comprises a dust seal member providedto the ribbon cable, the dust seal member engaging a dust sealengagement portion of the carrier body.
 15. The ferrule assembly ofclaim 14, wherein the dust seal engagement portion is defined by acut-out along the second channel.
 16. A method for terminating at leastone fiber of a ribbon cable in a ferrule and assembling an opticalconnector, which comprises: providing the ferrule having a mating face,at least one groove for receiving the fiber and at least onethrough-hole; disposing and terminating the fiber in the ferrule, withan end of the fiber coplanar to the mating face of the ferrule;providing an alignment member holder having at least one alignmentmember of a first length and a first channel for the ribbon cable;providing a carrier body having at least two biasing member captureportions, each of the biasing member capture portions providing anopening for receiving a biasing member therein, and a second channel forthe ribbon cable disposed between the biasing member capture portions;attaching the alignment member holder and the carrier body such that thefirst channel is contiguous with the second channel; and inserting thealignment member in the through-hole of the ferrule and disposing theribbon cable in the first and second channels,
 17. The method of claim16, which further comprises: providing a dust seal member to the ribboncable; and providing the carrier body with a dust seal engagementportion such that the dust seal member is engaged to the dust sealengagement portion when the ribbon cable is disposed in the first andsecond channels.
 18. The method of claim 16, which further comprises:providing a housing for the optical connector; and disposing theassembled ferrule, alignment member holder and carrier body assembly inthe housing.
 19. The method of claim 18, which further comprises:attaching a strain relief member having a curved channel to the housingsuch that strain relief is provided to the ribbon cable.
 20. An opticalconnector assembly which comprises: a first optical connector forterminating at least one fiber of a first ribbon cable in a firstferrule, the first optical connector including: the first ferrule havinga mating face, at least one groove for receiving the fiber of the firstribbon cable and at least one through-hole; a first alignment memberholder having at least one alignment member and providing a firstchannel for the first ribbon cable, the alignment member beinginsertable in the through-hole of the first ferrule and having a firstlength such that an end of the alignment member extends beyond themating face of the first ferrule when inserted in the through-hole ofthe first ferrule; a first carrier body attachable to the firstalignment member holder, the first carrier body having at least twobiasing member capture portions, each of the biasing member captureportions providing an opening for capturing a biasing member thereinwhen the first alignment member holder and the first carrier body areattached; a first housing to receive the first ferrule, first alignmentmember holder and first carrier body; and a strain relief member, thestrain relief member attachable to the first housing to provide strainrelief to the first ribbon cable.
 21. The optical connector assembly ofclaim 20, wherein the first alignment member holder includes first andsecond guides insertable into the openings of the biasing member captureportions such that when the first alignment member holder and the firstcarrier body are attached, the first alignment member holder is movableonly along the mating axis.
 22. The optical connector assembly of claim20, wherein the first alignment member holder includes a through-holeand the alignment member inserted into the through-hole of the firstalignment member holder such that the end of the alignment memberextends beyond the first alignment member holder in the direction of thefirst ferrule.
 23. The optical connector assembly of claim 20, whereinthe first ferrule further includes a second through-hole and the firstalignment member holder further includes a second alignment member, thesecond alignment member being insertable in the second through-hole andhaving a second length such that an end of the second alignment memberstays within the second through-hole and is recessed from the matingface of the first ferrule when the first optical connector is assembled.24. The optical connector assembly of claim 20, wherein the firstcarrier body further includes a ferrule assembly release member, theactuation of which allows the first carrier body to be removable fromthe first housing of the first optical connector.
 25. The opticalconnector assembly of claim 20, wherein the first carrier body furtherincludes at least one latch to latch the first carrier body to the firsthousing of the first optical connector.
 26. The optical connectorassembly of claim 20, which further comprises a first dust seal memberprovided to the first ribbon cable, the first dust seal member engaginga dust seal engagement portion of the first carrier body.
 27. Theoptical connector assembly of claim 20, which further comprises: asecond optical connector for terminating at least one fiber of a secondribbon cable in a second ferrule, the second optical connector mateablewith the first optical connector and including: the second ferrulehaving a mating face, at least one groove for receiving the fiber of thesecond ribbon cable and at least one through-hole; a second alignmentmember holder having at least one alignment member and providing a firstchannel for the second ribbon cable, the alignment member beinginsertable in the through-hole of the second ferrule and having a thirdlength such that an end of the alignment member extends beyond themating face of the second ferrule when inserted in the through-hole ofthe second ferrule; a second carrier body attachable to the secondalignment member holder, the second carrier body having at least twobiasing member capture portions, each of the biasing member captureportions providing an opening for capturing a biasing member thereinwhen the second alignment member holder and the second carrier body areattached; and a second housing to receive the second ferrule, secondalignment member holder and second carrier body.
 28. The opticalconnector assembly of claim 27, wherein the first ferrule is identicalto the second ferrule, the first alignment member holder is identical tothe second alignment member holder, and the first carrier body isidentical to the second carrier body.
 29. The optical connector assemblyof claim 20, wherein the strain relief member includes a curved channel.